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Finding the Fourth Proportional to 620.60, 856.42 and 387.72

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Solution

The fourth proportional to 620.60, 856.42 and 387.72 is: 535.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.60 : 856.42 = 387.72 : x
  2. Step 2: Convert to fraction form
    620.60/856.42 = 387.72/x
  3. Step 3: Cross multiply
    620.60x = 856.42 × 387.72
  4. Step 4: Simplify right side
    620.60x = 332,051.16
  5. Step 5: Solve for x
    x = 332,051.16/620.60
  6. Step 6: Final answer
    x = 535.05

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.